FDA approves first drug to treat smallpox

The United States Food and Drug Administration (FDA) approved on Friday TPOXX (tecovirimat), the first drug with an indication for treatment of smallpox.

Though the World Health Organization declared smallpox, a contagious and sometimes fatal infectious disease, eradicated in 1980, there have been concerns that smallpox could be used as a bioweapon, according to FDA.

"To address the risk of bioterrorism, Congress has taken steps to enable the development and approval of countermeasures to thwart pathogens that could be employed as weapons," said FDA Commissioner Scott Gottlieb.

Prior to its eradication in 1980, variola virus, the virus that causes smallpox, was mainly spread by direct contact between people. Symptoms typically began 10 to 14 days after infection and included fever, exhaustion, headache and backache. A rash initially consisting of small, pink bumps progressed to pus-filled sores before finally crusting over and scarring.

TPOXX's effectiveness against smallpox was established by studies conducted in animals infected with viruses that are closely related to the virus that causes smallpox, and was based on measuring survival at the end of the studies, reports Xinhua.

TPOXX was approved under the FDA's Animal Rule, which allows efficacy findings from adequate and well-controlled animal studies to support an FDA approval when it is not feasible or ethical to conduct efficacy trials in humans.